Search Results (170)

Introduction: Chagas disease, caused by the protozoan Trypanosoma cruzi, remains a major public health concern due to the limited effectiveness of current treatments, especially in the chronic stage. Objective: Here, we wanted to advance a library of 30 N,N′-disubstituted diamines as promising antichagasic agents and gain insight into the mechanism of action. Methods: The library was evaluated for activity against the T. cruzi amastigote stage and trypanocidal efficacy. In addition, selected compounds were tested as potential polyamine transport inhibitors, and a fluorescent analog was employed to investigate compound internalization. Results: Five compounds exhibited potent activity (pIC₅₀ > 6.0), particularly those with short aliphatic linkers (3–6 carbon atoms), suggesting a structure–activity relationship favouring shorter chains. Mechanistic studies showed that compound 3c strongly inhibited polyamine transport, a vital pathway in T. cruzi, though this was not a universal mechanism among active hits, indicating the potential for multiple targets. A fluorescent analog confirmed intracellular uptake in amastigotes but lacked antiparasitic activity, likely due to disrupted pharmacophoric features. Importantly, none of the compounds demonstrated trypanocidal activity in long-term assays, and some showed cytotoxicity, particularly in the benzyloxy-substituted series. Conclusions: These findings position N,N′-disubstituted diamines as a viable scaffold for Chagas disease drug discovery. However, further optimization is required to enhance selectivity, achieve trypanocidal effects, and better understand the underlying mechanisms of action. Full article

Chagas disease remains a significant neglected tropical disease that predominantly affects vulnerable populations in rural, low-income areas of Latin America. The management of this condition is severely hindered by the limitations of current therapies, which are characterized by substantial toxicity, diminished efficacy during the chronic phase, and the emergence of parasitic resistance. Given the promising activity of SB-83 (a 2-aminothiophenic derivative) against Leishmania spp., the present study sought to evaluate its trypanocidal activity against Trypanosoma cruzi. The results showed that SB-83 exhibited potent inhibitory effects on the epimastigote forms of T. cruzi (IC₅₀ = 6.23 ± 0.84 μM), trypomastigotes (EC₅₀ = 7.31 ± 0.52 μM) and intracellular amastigotes (EC₅₀ = 5.12 ± 0.49 μM). Furthermore, the cellular proliferation assay results indicated CC₅₀ values of 77.80 ± 2.05 µM for LLC-MK2 CCL-7 and 24.21 ± 1.2 µM for Vero CCL-87, with a selectivity index above 10 for LLC-MK2 cells. In addition, the compound increased TNF-α, IL-12, nitric oxide, and ROS while decreasing IL-10. Moreover, in silico and in vitro assays confirmed its binding to trypanothione reductase, disrupting redox balance. Flow cytometry further revealed apoptosis induction in trypomastigotes, whereas electron microscopy showed cellular disruption and organelle disorganization. Therefore, SB-83 demonstrated potent activity against the TcI-resistant strain linked to Chagas cardiomyopathy at non-toxic concentrations for host cells, supporting its potential as a therapeutic candidate. Full article

Background/Objectives: Chagas disease remains a major unmet medical need due to the limited efficacy and safety of current therapies. Here, we investigated sixteen thiosemicarbazone (TSC) derivatives as cruzain inhibitors using an integrated in silico/in vitro workflow. Methods: Docking against cruzain (PDB 3KKU) guided hit prioritization and correlated with enzyme inhibition; validation by redocking supported the protocol’s reliability. Results: The top compounds—H7, H10 and H11—showed potent cruzain inhibition (IC₅₀ = 0.306, 0.512 and 0.412 µM, respectively) and low-micromolar trypanocidal activity, with negligible cytotoxicity in human fibroblasts (CC₅₀ > 64 µM) and favorable selectivity. Structure–activity insights highlighted the role of expanded aromatic systems and electron-donating groups in enhancing binding within S2/S1′ subsites, while nitro substituents were associated with higher cytotoxicity. In silico ADMET parameters supported oral drug-likeness and acceptable metabolic liabilities. Conclusions: Overall, these data position TSCs as promising anti-T. cruzi leads and underscore the value of rational design against cruzain. Full article

Chagas disease is caused by the protozoan Trypanosoma cruzi, and its current treatment is limited to the use of two nitroderivatives, benznidazole (Bz) and nifurtimox; however, their toxicity often leads to discontinuation, justifying the search for new therapeutic options. The biological activity of quinones has long shown efficacy towards pathogenic microorganisms. In our previous investigations, two naphthoquinones combining ortho- and para-quinoidal moieties exhibited remarkable trypanocidal activity and presented low toxicity to host cells. Here, these two active compounds were further assessed. On trypomastigotes and epimastigotes, brominated (NQ1) and chlorinated (NQ2) nor-beta-lapachone-derived 1,2,3-triazoles were more active than Bz, presenting IC₅₀/24 h values in the range of 0.8 to 3.1 µM. NQ1-treated epimastigotes showed a mitochondrial impairment and reactive oxygen species (ROS) production under electron microscopy and flow cytometry. The in vitro evaluation of both combinations of compounds with Bz indicated an additive interaction. In vivo, oral treatment with NQ1 reduced parasitemia in an acute model, with no evidence of toxicity. The treatment also led to a reduction in myocarditis, decreasing the PR interval in electrocardiographic analysis and reversing the sinus bradycardia caused by infection. These data suggest that T. cruzi mitochondrion are part of the NQ1 mechanism of action. In vivo, this compound presented moderate trypanocidal and promising anti-inflammatory activity. Its combination with Bz could enhance current therapeutic protocols and should be better explored in the future. Full article

Background: In recent years, compounds known as Proteolysis Targeted Chimeras (PROTACs) have revitalized the field of bioactive molecule design. These compounds promote proteolysis of therapeutic targets by recruiting them to ubiquitin ligases. One of the most commonly used classes of compounds in the synthesis of PROTACs are immunomodulatory imides (IMiDs), such as thalidomide (TLD), which interact with the E3 ligase CRL4^CRBN via the CULT domain of the cereblon protein (CRBN). This domain has been identified in proteins across various phylogenetic groups, including trypanosomatids, leading to the hypothesis that IMiD-derived PROTACs should be active in these organisms. Methods: The trypanocidal activity of the PROTAC dBET1 and its separated components (JQ1 and TLD) were assayed using a T. cruzi strain expressing β-glalactosidase. Potential CRL4-E3L complexes from humans and trypanosomatids were assembled in silico with MultimerMapper. The IMiD-binding site of HsCRBN and its trypanosomatid homologs were analyzed using molecular dynamics and docking simulations. Results: We demonstrate that the compound dBET1 does not function as a PROTAC in Trypanosoma cruzi. In silico structural analysis of CRL4-E3L complex orthologs revealed that the trypanosomal CULT-containing protein is not part of such a complex. Molecular dynamics simulations showed that the pocket of this CULT domain is smaller than that of mammalian CRBN and cannot accommodate IMiDs within. Conclusions: We underscore the importance of functional and structural validation in drug discovery, particularly when extrapolating mechanisms between evolutionarily distant species. While PROTACs hold promise in human therapeutics, our work advocates for re-evaluating the rationale behind thalidomide-based PROTACs in trypanosomatid research. Full article

Background/Objectives: Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi, which currently affects around 8 million people worldwide. The therapeutic arsenal against T. cruzi is so far limited to only two approved drugs, benznidazole and nifurtimox, that have considerable side effects and limited efficacy in the chronic stage of the disease. Here, we have resorted to supervised phenotypic machine learning models to explore drug repurposing opportunities and identify potential new therapeutic solutions for Chagas disease. Methods: More than 100,000 bioactivity data points were retrieved from ChEMBL and carefully curated according to the data-centric machine learning paradigm. After curation, two datasets comprising 344 compounds tested against T. cruzi Y strain trypomastigotes and 785 compounds tested against Tulahuen strain amastigotes were obtained and used to infer ensemble learning models with excellent average and early enrichment metrics in retrospective screening experiments (AUROC > 0.96 and EF_0.01 > 58). A prospective screening campaign was then performed on DrugBank and the Drug Repurposing Hub databases, submitting eight in silico hits for experimental confirmation. Results: Six of the in silico hits confirmed their predicted trypanocidal effects. Conclusions: We have built portable meta-classifiers capable of identifying small molecules with trypanocidal activity against amastigotes, the clinically most relevant stage of T. cruzi. The predictive ability of this meta-classifier was experimentally validated. Full article

Background: Chagas disease and leishmaniasis remain public health concerns. Despite the existence of approved medications for the treatment of these diseases, most patients discontinue treatment due to long drug regimens and/or the severe side effects of these drugs. This leads to treatment failure and potential future drug resistance. Therefore, the search for new molecules with trypanocidal activity, low cytotoxicity, and high selectivity is essential to address this challenge. Methods: In this work, three series (a, b, and c) of pyridine-2,5-dicarboxylate esters were synthesized using different β-keto-esters bearing naturally occurring fragments and 1,2,3-triazine-1-oxides via the inverse electron demand Diels–Alder (IEDDA) reaction. The structural elucidation of the compounds was performed using NMR (¹H and ¹³C) and HRMS, and the crystal structure of compound 6a was also obtained. Furthermore, a biological assay was performed for all synthesized and characterized compounds to determine their cytotoxicity against Trypanosoma cruzi, Leishmania mexicana, and the J774.2 macrophage cell line. Finally, the in silico determination of their pharmacokinetic and toxicological properties was performed using the SwissADME and ProTox 3.0 platforms. Results: Compounds 3a, 4a, 5a, 4b, and 8c had the highest anti-Trypanosoma cruzi activity against both strains (IC₅₀ ≤ 56.68 µM). Compounds 8b, 10a, 9b, and 12b had considerable leishmanicidal activity against Leishmania mexicana against both strains (IC₅₀ ≤ 161.53 µM). Furthermore, in silico prediction of ADMET properties suggest that these pyridine compounds possess good pharmacokinetic profile. The results are also consistent with low in vitro cytotoxicity and high selectivity. Conclusions: The synthesized pyridine-2,5-dicarboxylate esters have promising activity against Trypanosoma cruzi and Leishmania mexicana, with low cytotoxicity and good drug-like properties, suggesting that these compounds are potential candidates for further evaluation as new treatments for Chagas disease and leishmaniasis. Full article

Background/Objectives: Temporizin-1, a hybrid antimicrobial peptide derived from the combination of Temporin A, Gramicidin peptide, and a poly-leu sequence, has strong trypanocide activity against Trypanosoma cruzi and moderate cytotoxicity towards mammalian cells. In this study, we investigated the mode of action of the peptide upon interaction with protozoan and eukaryotic membranes. Methods: To this end, we conducted a series of biophysical assays using liposomes as biomimetic models, along with fluorescence-based experiments such as lipid mixing, membrane leakage, and assays involving Thioflavin and Laurdan. Results: Temporizin-1 displayed potent membranolytic activity on protozoan and eukaryotic membranes, causing significant membrane fusion and leakage with consequent pore formation. In addition, we also performed structural studies on liposome interaction, where we observed a helical structure that is conserved during membrane interaction. The NMR study confirms all the data obtained, providing both the structure of free Temporizin-1 in solution and the way it interacts with micelles. Moreover, Temporizin-1 demonstrated high selectivity against intracellular forms of T. cruzi and exhibited an additive effect when combined with benznidazole, highlighting its promising therapeutic activity. Conclusions: In conclusion, elucidating the mechanism of action of Temporizin-1 is essential for optimizing its structure and improving target selectivity, and driving the rational design of next-generation antimicrobial peptides by applying chemical strategies and delivery system’s conjugation. Full article

The neglected Chagas disease, a zoonosis caused by the Trypanosoma cruzi parasite, has limited treatment options like nifurtimox and benznidazole, known for their toxic effects and controversial efficacy. Natural products present opportunities for therapeutic alternatives, particularly in Chile, which has a rich variety of endemic flora. This study focused on the Chilean Buddleja globosa, evaluating the antioxidant activities and biological effects of its methanolic extract (MET) and BG500, an enriched iridoid fraction (6-O-methylcatalpol), against T. cruzi trypomastigotes. Although the trypanocidal activity of the extract was significantly lower than that of nifurtimox (280 ± 3.5 vs. 5.0 ± 0.5), its selectivity was comparable (selectivity index > 15). The MET and enriched fraction also induced hyperpolarization of mitochondrial membrane potential (ΔΨm). In silico docking studies suggested that T. cruzi’s Old Yellow (OYE) could be a potential target for 6-O-methylcatalpol. This work provides the first report on the potential trypanocidal activity of a B. globosa extract, highlighting the need for further studies to connect ΔΨm and OYE inhibition to the effects of 6-O-methylcatalpol. Full article

Background/Objectives: Trypanosoma evansi (T. evansi) is an etiological agent of surra, and it causes significant economic losses in livestock. Rising trypanocide resistance demands alternatives that control parasitemia while mitigating oxidative and genotoxic damage. Therefore, the present study was designed to explore both the in vivo and in silico potential of Zingiber officinale (Z. officinale) as a novel phytotherapy to counter growing resistance against conventional trypanocides. Methods: Methanolic extract of Z. officinale (MZ) was orally administered at dosages of 200 mg/kg (MZ 200), 400 mg/kg (MZ 400), and 800 mg/kg (MZ 800) on a daily basis to the experimentally infected mice and compared against treated control (TC) and untreated control (UC) groups. After the infection, different parameters such as parasitemia counts, body weight changes, and the survival of infected mice were monitored for up to 7 days post-infection, while hematobiochemical parameters, oxidative stress profiles (catalase, malondialdehyde, and superoxide dismutase), and genotoxicity in brain tissues were compared at the end of the trial. Moreover, computational tools were used to predict the affinities of key bioactive compounds with twenty-one essential proteins of T. evansi. Results: The findings showed that the administration of MZ significantly (p < 0.05) reduced parasitemia and improved the survival rates in the experimentally infected mice in a dose-dependent manner. Noteworthy, significant (p < 0.05) improvements in hematological parameters and liver enzyme profiles were also recorded in MZ-treated groups. Compared to the untreated control, MZ-treated groups showed a significant amelioration in oxidative stress and genotoxicity in brain tissue in a dose-dependent fashion. The current study’s findings suggest that MZ potentially inhibits various essential proteins of T. evansi, including adenosine transporter-1, casein kinase, leucyl-tRNA synthetase, and multidrug resistance E protein. Among its constituents, 6-Isoshogaol and 6-Gingerol showed the most stable interactions in the molecular dynamics simulation. Conclusions: MZ efficiently reduced parasitemia, oxidative stress, and genotoxicity, and increased the survival rate in infected mice, suggesting it as a promising natural trypanicidal agent. Full article

Background/Objectives: The study of biological activity of plants and their metabolites is an important approach for the discovery of new active material. However, little is known of the properties of the Microlicia genus. In addition to natural products, nanotechnology demonstrates considerable potential in pharmacotherapy. The utilization of nanoemulsions holds considerable promise in enhancing the efficacy of drugs, reducing dose, and therefore, lowering of toxic effects. Methods: In this context, antimicrobial and trypanocidal activities were evaluated to the free and encapsulated essential oil from M. graveolens in oil-in-water (o/w) nanoemulsion. Results: This oil is composed mainly of cis-pinocarvyl acetate (~80.0%). The nanoemulsions were prepared by phase inversion method and showed mean particle size of 58 nm, polydispercity index of 0.09, pH 7.8, zeta potential of −21.9 mV, electrical conductivity of 0.38 mS/cm, and good stability. The essential oil was active against all five Gram-positive bacteria tested, and the formulation enhanced this ability. The cytotoxicity effect on L929 cells was also reduced after encapsulation of this oil in o/w nanoemulsion. In addition, the oil and the nanoemulsion were able to inhibit the growth of Trypanosoma cruzi. Conclusions: Thus, the development of a nanoemulsion loaded with M. graveolens essential oil is an easy and low-cost way to obtain and deliver the cis-pinocarvyl acetate compound as well as allow its use in the treatment of diseases caused mainly by the genus Listeria and Staphylococcus. Full article

Trypanosoma cruzi is the protozoan parasite that causes Chagas disease, affecting approximately 6–7 million people worldwide. The current treatment lacks efficacy in the chronic phase of the disease. This study aims to determine the in vitro synergistic activity of concomitant therapy (benznidazole with β-caryophyllene oxide) against Trypanosoma cruzi, assess its cytotoxicity, and propose the mechanism of this synergism through in silico analysis. The tested concentrations of the treatment demonstrated hemocompatibility (<5% hemolysis) and no cytotoxicity (>80% cell viability). Additionally, synergistic activity against the parasite was confirmed, reducing epimastigote viability by up to 80%. In this work, in silico analysis revealed that β-caryophyllene oxide also binds to the T. cruzi ABC channel in regions localized to amino acids 108–271 and 399–558, suggesting this interaction could inhibit it. This treatment emerges as a promising candidate for Chagas disease therapy. It lacks cytotoxic and hemolytic activity while exhibiting synergism against the parasite, such as through the inhibition of ABC channels, as suggested in silico. Full article

Background: Worldwide, the number of cases of parasitic diseases has been increasing; however, available treatments have variable adverse effects and low efficacy, mainly in Neglected Tropical Diseases such as Chagas disease and Leishmaniasis. Therefore, the development of new and more effective antiparasitic drugs is important. Natural products are the source of secondary metabolites with different biological activities, such as antibacterial, anticancer, anti-inflammatory, and antiparasitic. Objectives: In this work, secondary metabolites (phenols and terpenes) from natural products were selected to be evaluated against the epimastigotes of NINOA and A1 strains of Trypanosoma cruzi and the promastigotes of M379 strain and FCQEPS native isolate of Leishmania mexicana. Additionally, their cytotoxicity and selectivity index were determined. Methods: Eighteen secondary metabolites were evaluated in vitro against T. cruzi epimastigotes and L. mexicana promastigotes; additionally, their cytotoxicity on the J774.2 macrophage cell line was determined. Results: The compounds l-(-)-menthol (14, IC₅₀ = 24.52 µM) and β-citronellol (11, IC₅₀ = 21.54 µM) had higher trypanocidal activity than the reference drug (benznidazole) against NINOA and A1 strains of T. cruzi, respectively. On the other hand, para-anisyl alcohol (4, IC₅₀ = 34.89 µM) had higher leishmanicidal activity than the reference drug (glucantime^®) against M379 and the FCQEPS native isolate of L. mexicana. Finally, in silico, the determination of their pharmacokinetic and toxicological properties showed that they are promising candidates for oral and topical uses. Conclusions: This study opens the possibility of using secondary metabolites as scaffolds for access to the development of new molecules for the treatment of parasite diseases. Full article

Chagas disease (ChD) caused by Trypanosoma cruzi remains a major public health concern, affecting approximately 8 million people worldwide. However, the number of undiagnosed cases is likely much higher. Existing treatments rely on benznidazole and nifurtimox which, despite their efficacy during the acute phase of infection, are often associated with severe side effects that can be life-threatening. As a promising alternative, actinomycetes—which are renowned for producing pharmacologically and industrially relevant metabolites—have demonstrated potent antimicrobial properties; however, their antiparasitic potential remains largely unexplored. This study evaluated the anti-trypanocidal activities of extracellular metabolites produced by Streptomyces thermocarboxydus strain Chi-43 (ST-C43) and Streptomyces sp. strain Chi-104 (S-C104) against epimastigote, trypomastigote, and amastigote forms of T. cruzi. The strains were cultured in ISP2 broth, and their extracellular metabolites were assessed via antiparasitic diffusion assays in microplates. The 50% lethal concentration (LC₅₀) values ranged from 102 to 116 μg/mL against epimastigotes and trypomastigotes. The antiparasitic activity was confirmed through 3-(4,5-dimetiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based spectrophotometric assays and optical microscopy. Toxicity assays revealed that the extracellular metabolites were non-toxic to Artemia salina, non-cytotoxic to Huvecs, and non-hemolytic to human erythrocytes. Dose–response regression analysis showed statistically significant differences (p ≤ 0.05). LC-MS/MS analysis identified amphomycin and K-252c aglycone staurosporine as the active antiparasitic compounds. These findings highlight the potential of Streptomyces-derived extracellular metabolites as novel, selective, and safe anti-T. cruzi agents. Nevertheless, further studies in murine or preclinical models are needed to validate their efficacy and support future clinical applications for the treatment of ChD. Full article

The phytochemical screening of extracts of Tacca leontopetaloides tubers has afforded the isolation of two novel chalcones, tarkalynins A and B, along with taccalonolide A and its 12-propanoate. The screening of Zanthoxylum zanthoxyloides stem bark yielded taraxerol acetate, dihydrochelerythrin and fagaramide. These compounds were obtained through column and thin-layer chromatography and identified using NMR and LC-HRMS. The compounds were tested against Trypanosoma brucei brucei s427 and its multi-drug-resistant clone B48, against Trypanosoma evansi, Trypanosoma equiperdum and Trypanosoma congolense, and against Leishmania mexicana. Cytotoxicity was tested against the human HEK293 cell line. The highest activities were observed with dihydrochelerythrin and fagaramide against T. b. brucei s427 and B48, T. evansi, and L. mexicana, with EC₅₀ values of 1.37, 2.559, 1.09, and 5.44 µM and 17.8, 10.9, 10.9, and 13.3 µM, respectively. In addition, tarkalynin A and taraxerol acetate displayed promising activity against T. equiperdum (EC₅₀ = 21.4 and 21.3 µM, respectively). None of these compounds showed significant cross-resistance with existing trypanocides (RF ≈ 1; p > 0.05). The compounds displayed low toxicity to human cells, with most exhibiting no growth inhibition at concentrations of 100, or even 300 µM. This report provides further evidence of the potential use of natural products for combating parasitic diseases. Full article